Q.

The product of all solutions of the equation e5(logex)2+3=x8, x>0, is:          [2025]

1 e2  
2 e  
3 e8/5  
4 e6/5  

Ans.

(3)

We have, e5(logex)2+3=x8, x>0

Taking log on both sides, we get

5(ln x)2+3=8lnx  5(ln x)2+38lnx=0

Put ln x = t

 5t28t+3=0  t1+t2=85

  ln x1+ln x2=8/5  ln(x1x2)=8/5  x1x2=e8/5.